TY - JOUR
T1 - Monensin-resistant LLC-PK1 cell mutants are affected in recycling of the adenylate cyclase-stimulating vasopressin V2-receptor
AU - Jans, David A.
AU - Jans, Patricia
AU - Luzius, Heike
AU - Fahrenholz, Falk
PY - 1991/1/1
Y1 - 1991/1/1
N2 - The ionophore monensin was found to markedly reduce the rate of return of vasopressin V2-receptors to the membrane following down-regulation with [Arg8]vasopressin (AVP), as well as hormone dissociation (unloading) from cells following ligand binding and internalization in LLC-PK1 renal epithelial cells. Monensin-resistant LLC-PK1 mutants were isolated and characterized for V2-receptor recycling. Whilst the MN-41 mutant appeared to be impaired in [3H]AVP internalization, the MN-11 and MN-21 mutants exhibited parental V2-receptor binding and internalization, but markedly impaired receptor recycling subsequent to ligand-dependent receptor down-regulation. Unloading subsequent to ligand binding and internalization at 37°C was also much slower in the mutants either at 37°C or 23°C. In contrast, unloading subsequent to binding at 23°C, or to binding at 37°C in the presence of NH4Cl, was comparable in LLC-PK1 and mutant cells implying the active nature of the recycling process impaired in the mutants. The mutations conferring resistance to monensin thus concomitantly impaired V2-receptor recycling in the mutants. Results argue for a monensin-sensitive endosomal/lysosomal pathway for the renal V2-receptor, representing the first such report for an adenylate cyclase stimulating receptor.
AB - The ionophore monensin was found to markedly reduce the rate of return of vasopressin V2-receptors to the membrane following down-regulation with [Arg8]vasopressin (AVP), as well as hormone dissociation (unloading) from cells following ligand binding and internalization in LLC-PK1 renal epithelial cells. Monensin-resistant LLC-PK1 mutants were isolated and characterized for V2-receptor recycling. Whilst the MN-41 mutant appeared to be impaired in [3H]AVP internalization, the MN-11 and MN-21 mutants exhibited parental V2-receptor binding and internalization, but markedly impaired receptor recycling subsequent to ligand-dependent receptor down-regulation. Unloading subsequent to ligand binding and internalization at 37°C was also much slower in the mutants either at 37°C or 23°C. In contrast, unloading subsequent to binding at 23°C, or to binding at 37°C in the presence of NH4Cl, was comparable in LLC-PK1 and mutant cells implying the active nature of the recycling process impaired in the mutants. The mutations conferring resistance to monensin thus concomitantly impaired V2-receptor recycling in the mutants. Results argue for a monensin-sensitive endosomal/lysosomal pathway for the renal V2-receptor, representing the first such report for an adenylate cyclase stimulating receptor.
KW - Endocytosis
KW - Monensin
KW - Receptor recycling
KW - Renal epithelial cell mutant
UR - http://www.scopus.com/inward/record.url?scp=0025918704&partnerID=8YFLogxK
U2 - 10.1016/0303-7207(91)90215-E
DO - 10.1016/0303-7207(91)90215-E
M3 - Article
C2 - 1797584
AN - SCOPUS:0025918704
SN - 0303-7207
VL - 81
SP - 165
EP - 174
JO - Molecular and Cellular Endocrinology
JF - Molecular and Cellular Endocrinology
IS - 1-3
ER -